Split iai_maps into three separate packages

* iai_semantic_maps: Semantic maps of our lab(s)
* iai_maps: 2D maps and launch files
* iai_kitchen_defs: URDF files and Gazebo information
adapted OWL and Prolog files. Most Prolog files are not needed any more since the map utils have been moved to knowrob_map_tools
updated launch file for json_prolog service with new syntax
corrected package names in package.xml
also fixed package names in CMakeLists
adapted launch files to the new package structure
removed rviz launch file; the respective rviz config had already been removed
Added Readme.md
Merge pull request #6 from knowrob/master

Catkinized iai_maps and adapted it to the new version of KnowRob